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temperature ceramics and metals. Considerable research is
underway, which deserves a focused review not included in
the present discussion. This article seeks to examine application of thermal spray technology in thick film or mesoscale
electronic devices and sensor materials where an untapped
opportunity clearly exists.
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Thick film electronics based on devices with dimensions
in the 10 µm to mm range represent a multibillion dollar industry. These devices rely on ceramic and metal components
typically built via screen printing techniques with appropriate co-firing at temperatures from 700° to 1400°C, depending on the nature of the ceramic material or device. This
technique—although the mainstay of the power electronics
industry—has limitations, as it is built on traditional 2D
stacking and co-firing. Numerous opportunities to incorporate thermal spray technology exist, for example, in component-integrated electronics and thick film sensors where there
is a need to integrate electronics or sensors with a structural
component. Further, many applications seek ceramic or
metallic interconnection and device integration with polymeric carrier materials. It is in precisely these situations that
thermal spray offers a novel extension to traditional thick
film technology.
Thermal spray also offers the ability for high throughput
with in situ application of metals, ceramics, and polymers,
in most cases without requiring significant thermal input to
the substrate. The technology also can be adopted for 3D
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ADVANCED MATERIALS & PROCESSES • NOVEMBER-DECEMBER 2013
manufacturing and is customizable for a range of dimensions.
What is more, the process allows significant materials versatility along with the ability to integrate with other hybrid
manufacturing systems, such as laser annealing or micromachining. Thermal spray can readily fabricate insulated metal
substrates, but with specialized configurations, it can also be
used for fine scale printing or direct writing. This has led to
considerable interest in applying the technology in electronics and sensor manufacturing. Figure 1 showcases potential
opportunities for thermal spray in functional materials and
electronics.
Critical challenges remain in order to realize this potential. The key issue is to understand the process-structureproperty relationships for functional systems. In addition, the
rapid heating and cooling cycles of thermal spray processes
can affect not only extrinsic defects (e.g., porosity, interfaces), but also intrinsic materials issues such as metastability, stoichiometric variations, and oxidation states. The
technology can only be harnessed if adequate material properties are achieved. Advances in process science, technological precision, and an enhanced understanding of materials
behavior have spurred slow but steady penetration of thermal spray technology into various applications, and this is
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only expected to grow over the coming decades.
Sanjay Sampath is professor at
Stony Brook University, Center for Thermal Spray Research,
Rm 130, Heavy Engineering Building, NY 11794, 631/6329512, ssampath@ms.cc.sunyb.edu, www.ctsr-sunysb.org.